, 2004 and Milligan and Watkins, 2009), and we have recently shown that Ca2+ signalling in astrocytes is disturbed when influenced by inflammatory stimuli (Hansson, 2010). Two substances with proposed anti-inflammatory properties at extremely low concentrations, naloxone and ouabain, demonstrate an ability to limit the inflammatory PD0325901 induced alterations in astrocytes (Forshammar et al., 2011). We conclude that this is a note-worthy step in understanding astrocyte responses and neuroinflammatory mechanisms. There are more substances that have been proposed to have anti-inflammatory qualities and up-regulate or restore parameters related to inflammation especially

at extremely low concentrations in astrocytes. In the present study we wanted to examine a number of substances, which have anti-inflammatory effects on astrocytes, and we wanted to test them in LPS-activated microglia. The substances Cabozantinib concentration tested were naloxone, ouabain, and bupivacaine. We also

used some well-known classical anti-inflammatory substances, dexamethasone and corticosterone, as control substances. They attenuated both TNF-α and IL-1β releases. Glucocorticoids prevent swelling of cells and release of pro-inflammatory cytokines (Chao et al., 1992 and Lekander et al., 2009), and decrease the number of activated microglia (Hinkerohe et al., 2010). These two glucocorticoids are frequently used in acute pain states (De Oliveira et al., 2011). On the other hand, glucocorticoids can also cause extracellular accumulation of glutamate, which could cause excitotoxicity and acute stress (Jacobsson et al., 2006). Naloxone at ultralow concentration, prevented LPS induced down-regulation of Na+/K+-ATPase

(Forshammar et al., 2011), and down-regulated LPS-induced endomorphin stimulated Ca2+ transients in astrocytes (Block et al., 2012), as well as reversed down-regulation of the Na+ dependent glutamate transporter (Tsai et al., 2009). So far naloxone has not been able to decrease the release Celecoxib of pro-inflammatory cytokines in LPS-activated astrocytes or microglia. Instead a small increase of TNF-α was observed in microglia. Ouabain also enhances LPS down-regulated iNOS activity in peritoneal macrophages (Sowa and Przewlocki, 1997). It decreased the IL-1β release in astrocytes ( Forshammar et al., 2011), but showed a small increase of TNF-α in microglia. It can be speculated in if the increased release of TNF-α with ultralow concentrations of naloxone or ouabain might have a protective effect. Exogenous TNF-α as well as TNF-α produced by astrocytes, induces production of neurotrophic factors such as nerve growth factor (NGF) and glial cell line-derived neurotrophic factor GDNF by astrocytes ( Kuno et al., 2006). TNF-α as well as IL-1β are considered to initiate a cascade of activation of cytokines and growth factors.